Liquid immersed electric circuit breaker



Dec. 15, 1936. c. H. FLURSCHEIM LIQUID IMMERSED ELECTRIC CIRCUIT BREAKER Filed Nov. 12, 1935 Inventor" Cedric HuF lurscheim, by

is Aoto r'neg.

Patented Dec. 15, 1936 UNITED STATES PATENT OFFICE LIQUID IMMERSED ELECTRIC CIRCUIT BREAKER Cedric H. Flurscheim, Fleet, England, assignor to General Electric Company, a corporation of New York Application November 12, 1935, Serial No. 49,433 In Great Britain December 6, 1934 4 Claims. (Cl. 200-) This invention relates to liquid immersed electric circuit breakers and has particular reference to circuit breakers of the cross jet or blast type. The invention also has an important application to circuit breakers of the horizontal type the circuit a jet of oil from a source under pres sure is projected laterally across the path of the moving contact in order to assist in quenching the are produced. Circuit breakers have in other cases been arranged in which the jet of oil is produced by the pressure due to the actual arc itself.

A jet produced by the first mentioned or impulse method is effective for quenching relatively small currents but for larger currents it is less effective and the arc duration may become considerably greater, unless large energies are available. A jet on the other hand produced by the second or self-generated method is relatively inefficient for breaking small currents, but for larger currents it is very much more efllcient and the arc duration falls to a satisfactory value.

According to the present invention, a cross jet circuit breaker is provided with means whereby upon breaking the circuit both an" impulse jet and also a self-generated jet are produced across the path of the moving contact. The outlet passages for the jets after leaving the arcs may be separated or a common outlet passage may be provided.

In one embodiment of this invention, the circuit breaker is preferably fitted with a partition extending laterally with respect to the path of the moving contact and separating the cross jet passages into two groups having separate inlets, means being provided whereby 'oil under pressure is supplied to one group of cross jet passages during breaking of the circuit, the other group of cross jet passages being adapted to have oil forced therethrough by the pressure due to the arc itself.

The term group as employed herein with reference to the cross jet passages is intended to include a single passage or several parallel pas sages separated by dividing barriers or splitters. The two jets upon leaving the cross jet may conveniently converge into a common outlet passage which may for instance be a. relatively wide passage carrying the oil and the gases to a vent in any desired direction. The jets are preferably of insulating oil but other insulating or areextinguishing liquids, such as carbon tetrachloride, may be employed.

This invention will be more fully set forth in the following description referring to the accompanying drawing, and the features of novelty which characterize this invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

Referring to the drawing, the single figure thereof is an elevational view, partly in section,

of an electric circuit breaker constructed in accordance with this invention.

The circuit breaker as shown comprises a main body portion or housing I mounted upon a pillar or other suitable support 2. The housing, which contains a suitable arc-extinguishing liquid, such as oil, is provided with a horizontal extending insulating casing 3 surrounded by a rain or weather shield 4, preferably of ceramic material. Through the main body portion l passes a fixed conductor surrounded by an insulating bushing 5 and connected electrically to one terminal of the breaker 5 and to the moving contact 6 of the circuit breaker which cooperates with a fixed contact! at the other terminal of the breaker.

Across the path of the moving contact are formed by insulating material a series of cross 3 jet or cross blast passages 8 and another cross jet passage 9, the passages 8 being separated from the passage 9 by an insulating partition if). Upon initial breaking of the circuit in the abovedescribed baffle structure, oil is forced through the passage 9 by the pressure set up by the are occurring in the chamber H, the oil passing from the chamber H to the passage 9 through the inlet passage l2, as occurs in the usual explo sion pot constructions.

The cross jet passages 8, on the other hand, are connected through an inlet passage IS with the space M formed within the casing 3 and during breaking of the circuit oil is forced by means of mechanism contained within the main body portion l into the space It whence it passes through the passage l3 to the cross jet passages 8 as the contact 6 uncovers these passages. Thus two separate oil jets are formed and projected across the arc, the one jet being that set up through the passages 8 and being of an impulse type while the other jet is that formed by the oil traversing the passage 9 and is a self-generated jet. On leaving the respective cross jet passages the two jets in the apparatus shown pass into a common outlet passage ll which in turn exhaust into the venting chamber ll.

Accordingly, the are drawn between the contacts 6 and l is subjected to substantially uniform and eflective quenching action throughout the entire interrupting range of the breaker.

The mechanism for producing the forced or impulse oil jet may comprise pistons l5 movable within cylinders 16 and actuated simultaneously through linkage 11 with the movement or the moving contact 6. By way of example, the piston mechanism may conveniently be of the kind described in my above-identified copending application.

It should be understood that this invention is not limited to specific details of construction and arrangement thereof herein illustrated, and that changes and modifications may occur to one skilled in the art without departing from the spirit of this invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. An electric circuit breaker comprising a casing containing an arc-extinguishing liquid, relatively movable contacts separable in said liquid, cross blast baiiie structure through which the are formed between said contacts is drawn, and means for applying pressure to said liquid in accordance with the circuit opening operation, said baiiie structure forming liquid blast passages arranged transversely of said are so that upon initial separation of the contacts a liquid blast created by the arc pressure is directed across the arc through some of said passages and subsequently upon further separation of the contacts a liquid blast created by the aforesaid pressure applying means is directed across the arc through other of said passages.

2. An electric circuit breaker comprising a casing containing an arc-extinguishing liquid, cross blast baiiie structure immersed in said liquid, relatively movable contacts separable within said structure, and a piston operatively connected to the movable contact structure for applying pressure to said liquid in accordance with the circuit opening operation, said baiiie structure forming passages extending transverseiy of the arc path between said contacts and arranged so that the arc pressure Iormed upon initial separation of said contacts causes a blast of liquid through the arc at some of said passages and subsequently said piston drives liquid through said are at other oi said passages.

3. An electric circuit breaker comprising a casing containing an arc-extinguishing liquid, relatively movable contacts separable in said liquid, an insulating cross blast baiile coacting with said contacts at the point oi separation thereof, said baflle forming passages arranged transversely of the arc path between said contacts, one of said contacts comprising a movable rod arranged to uncover said passages in sequence, and means for transmitting pressure to the liquid within said casing in accordance with circuit opening operation, the arc pressure generated upon initial opening movement of said rod contact causing a liquid blast transversely of the arc through the passages initially uncovered by said rod and the pressure transmitting means causing a liquid blast across said are through the passages subsequently uncovered by said rod.

4. An electric circuit breaker comprising a casing containing an arc-extinguishing liquid, relatively movable contacts separable in said liquid, a cross blast baiiie surrounding said contacts at the point of separation thereof, said baiile iorming passages extending transversely of the arc path between said contacts, one of said contacts including a movable rod arranged successively to uncover said passages during the opening movement thereof, the passages initially uncovered by said rod being in communication with the arc pressure and arranged so that a liquid blast is directed through said passages across the arc, and a piston operatively connected to said rod contact for placing liquid in said casing under pressure in accordance with the circuit opening operation, the passages subsequently uncovered by said rod after said initial separation communicating with said liquid under pressure so that a liquid blast across the arc is likewise created by said piston, the passages communicating with said piston and the passages communicating with said arc pressure being separated so that said piston drives liquid through said are only after the initialarc pressure blast.

CEDRIC H. FLURSCHEIM. 

